5,505 research outputs found

    Holomorphic extension of smooth CR-mappings between real-analytic and real-algebraic CR-manifolds

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    We establish results on holomorphic extension of CR-mappings of class CC^\infty between a real-analytic CR-submanifold of \C^N and a real-algebraic CR-submanifold of \C^{N'}

    Energy dependence of current noise in superconducting/normal metal junctions

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    Interference of electronic waves undergoing Andreev reflection in diffusive conductors determines the energy profile of the conductance on the scale of the Thouless energy. A similar dependence exists in the current noise, but its behavior is known only in few limiting cases. We consider a metallic diffusive wire connected to a superconducting reservoir through an interface characterized by an arbitrary distribution of channel transparencies. Within the quasiclassical theory for current fluctuations we provide a general expression for the energy dependence of the current noise.Comment: 5 pages, 1 Figur

    Spatially resolved microwave pulsations of a flare loop

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    A microwave burst with quasi-periodic pulsations was studied with high spatial resolution using observations with the Nobeyama Radioheliograph (NoRH). We found that the time profiles of the microwave emission at 17 and 34 GHz exhibit quasi-periodic (with two well defined periods P 1 = 14–17 s and P 2 = 8–11 s) variations of the intensity at different parts of an observed flaring loop. Detailed Fourier analysis shows the P 1 spectral component to be dominant at the top, while the P 2 one near the feet of the loop. The 14–17 s pulsations are synchronous at the top and in both legs of the loop. The 8–11 s pulsations at the legs are well correlated with each other but the correlation is not so obvious with the pulsations at the loop top. For this P 2 spectral component, a definite phase shift, P 2 /4 ≈ 2.2 s, between pulsations in the northern leg and loop top parts of the loop have been found. The length of the flaring loop is estimated as L = 25 Mm (≈34 ) and its average width at half intensity at 34 GHz as about 6 Mm (≈8 ). Microwave diagnostics shows the loop to be filled with a dense plasma with the number density n 0 ≈ 10 11 cm −3, penetrated by the magnetic field changing from B 0 ≈ 100 G near the loop top up to B 0 ≈ 200 G near the north footpoint. A comparative analysis of different MHD modes of the loop demonstrates the possibility of the simultaneous existence of two modes of oscillations in the loop: the global sausage mode, with the period P 1 = 14–17 s and the nodes at the footpoints, and a higher harmonics mode (possibly with the radial wave number l > 1), with P 2 = 8–11 s
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